Hi, I searched how to add items in JList and try it. It adds in JList but there is something wrong. Please see the picture. All that I try has same results.

pic1 - shows that JList does not contain the items that I add.. or does not refresh
pic2 - is alsmost the same with pic1, only a scrollbar is added.Which means that the items are added, it just did not show.
pic3 - I click the scrollbar and the two items that I added show.